A COMPARISON OF VARIATIONS IN PLASMA LUTEINIZING HORMONE CONCENTRATIONS IN MALE AND FEMALE DOMESTIC CHICKENS (GALLUS DOMESTICUS) FROM HATCH TO SEXUAL MATURITY

1975 ◽  
Vol 67 (2) ◽  
pp. 211-223 ◽  
Author(s):  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Gallus Domesticus ◽  
Parallel Study ◽  
Stages Of Development ◽  
Male And Female ◽  
The Mean ◽  
Lh Secretion

SUMMARY Changes in plasma LH concentrations were followed in chickens of both sexes from hatch to sexual maturity using a radioimmunoassay. Mean levels of LH were lower in the females than in the males at all stages of development. These levels rose rapidly in both sexes during the first week after hatch to maxima of 6·5 ± 1·2 (s.e.m.) ng/ml (n = 6) in the males and 4·6 ± 0·6 ng/ml (n = 6) in the females. Thereafter levels of the hormone in the circulation stabilized in the males but fell over a period of 1 or 2 weeks in the females to 2·5–3 ng/ml. Plasma LH levels started to rise steeply in both sexes when they were between 16 and 19 weeks old at the same time as there was an increase in the rate of comb growth. Afterwards in six of the males studied in detail the mean plasma LH level rose significantly (P < 0·01) over a period of 5–8 weeks from 8·1 ± 1·2 to 13·2 ± 1·9 ng/ml. In a parallel study on six females the rate of LH secretion increased for approximately 3 weeks and then decreased for about the same period forming a prepubertal LH peak. The first eggs were laid between 22 and 25 weeks of age when mean plasma LH levels had fallen to about 1·8 ng/ml. The mean plasma LH level in these hens when they were laying (1·8 ± 0·3 ng/ml) was significantly lower (P < 0·01) than when they were sexually immature (2·7 ± 0·3 ng/ml). The duration of the period of rapid comb growth in each bird was closely related in the males to the time during which prepubertal LH levels were rising rapidly, and in the females to the duration of the prepubertal LH peak. Differences in mean plasma LH concentrations in individual birds of either sex before the onset of puberty appeared to be related to subsequent reproductive performance.

The effect of feed restriction on sexual maturity and initial reproductive performance of broiler pullets under different light treatments

1969 ◽  
Vol 9 (39) ◽  
pp. 417 ◽  
Author(s):  
RAE Pym ◽  
R Sledge
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Feed Restriction ◽  
Restricted Feeding ◽  
Egg Weight ◽  
Laying Performance ◽  
The Mean ◽  
The Difference ◽  
Lighting Systems

An experiment was conducted to examine the effect of restricted feeding under two lighting systems during the rearing period on the initial laying performance of broiler type pullets. The rearing treatments were imposed at nine weeks of age, removed at 22 weeks and the trial was discontinued at 36 weeks of age. The feeding treatments (restricted versus ad lib.) were arranged factorially with the lighting treatments (decreasing versus increasing). Birds reared on restricted feeding reached sexual maturity 16 days later than full fed birds, ate 17 per cent less feed to 22 weeks and gained seven per cent less in body weight to 24 weeks of age and ten per cent less to 36 weeks. Birds reared under the decreasing lighting regime reached sexual maturity at the same age as those reared under increasing lighting, ate five per cent more feed during the rearing and laying periods and gained five per cent more in body weight to 24 weeks. The mean weight of eggs laid between 24 and 34 weeks of age from pullets subjected concurrently to decreasing lighting and restricted feeding was approximately two grams heavier than that of the other three treatment combinations. Mean egg weight was one gram greater in the restricted than in the full fed group, although the difference was not statistically significant. Laying mortality was lower in the restricted fed group than in the full fed group.

scholarly journals Dietary choice for a balanced nutrient intake increases the mean and reduces the variance in the reproductive performance of male and female cockroaches

2016 ◽  
Vol 6 (14) ◽  
pp. 4711-4730 ◽  
Author(s):  
Harriet Bunning ◽  
Lee Bassett ◽  
Christina Clowser ◽  
James Rapkin ◽  
Kim Jensen ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Nutrient Intake ◽  
Male And Female ◽  
Dietary Choice ◽  
The Mean

EFFECT OF AN ANABOLIC STEROID (METANDIENON) ON PLASMA LH, FSH, AND TESTOSTERONE AND ON THE RESPONSE TO INTRAVENOUS ADMINISTRATION OF LRH

1976 ◽  
Vol 83 (4) ◽  
pp. 856-864 ◽  
Author(s):  
Pentti Holma ◽  
Herman Adlercreutz
Keyword(s):  
Luteinizing Hormone ◽  
Intravenous Administration ◽  
Anabolic Steroid ◽  
Plasma Levels ◽  
Oral Intake ◽  
Plasma Testosterone ◽  
Before And After ◽  
The Mean ◽  
Pre Treatment ◽  
Lh Secretion

ABSTRACT Plasma levels of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as well as the response of LH and FSH to the intravenous administration of 100 μg of luteinizing hormone releasing hormone (LRH) were measured in 16 well-trained athletes (mean age 30 years) before and after 2 months of daily oral intake of 15 mg of metandienon, an anabolic steroid (Anabolin®, 17α-methyl-17β-hydroxy-1,4-androstadien-3-one, Medica, Finland). All athletes continued to train regularly, just as they had done for several years. During administration of metandienon the mean plasma testosterone level fell 69%, from 29.4 ± 11.6 nmol/l to 9.1 ± 7.5 nmol/l. The mean plasma levels of LH and FSH also fell significantly (P < 0.001 and P < 0.01, respectively), both about 50%. Because LH and FSH levels were low after administration of the steroid the maximum stimulation values after LRH administration were also lower than pre-treatment values although the mean increments did not differ significantly before and after administration of the anabolic steroid. However, after treatment, the FSH response curve had a biphasic pattern in most subjects, with peaks at 10 to 20 and 50 to 60 min after the iv injection of LRH. Administration of LRH after the treatment period had no effect on FSH secretion in two subjects and no effect on LH secretion in one. Our results show that administration of an anabolic steroid causes a pronounced lowering of plasma levels of testosterone, LH and FSH but causes no gross alteration in the response of LH secretion to stimulation by LRH. The reason for the biphasic response pattern of FSH to LRH administration in most subjects is not known.

FACTORS INFLUENCING THE SECRETION OF LUTEINIZING HORMONE AND OVULATION IN RESPONSE TO ELECTROCHEMICAL STIMULATION OF THE PREOPTIC AREA IN RATS

1973 ◽  
Vol 58 (2) ◽  
pp. 163-176 ◽  
Author(s):  
M. E. VELASCO ◽  
I. ROTHCHILD
Keyword(s):  
Luteinizing Hormone ◽  
Preoptic Area ◽  
Threshold Level ◽  
Peak Serum ◽  
Ovariectomized Rats ◽  
Factors Affecting ◽  
Serum Lh ◽  
The Mean ◽  
Lh Secretion ◽  
Stimulation Of

SUMMARY Factors affecting luteinizing hormone (LH) secretion in response to stimulation of the preoptic area (POA) of the forebrain in rats were explored by determining serum LH levels after electrochemical stimulation of the POA. In rats made anovulatory by exposure to constant light (CLA rats), peak concentrations of LH in serum were found 2 h after stimulation with 5–15 mC, and 1 h after stimulation with 0·5–1 mC. The peak levels increased with increasing doses between 0·5 and 15 mC. The incidence of rats ovulating and the mean number of ovulations/rat were roughly proportional to the stimulating dose, but a plateau was reached between 5 and 10 mC. A threshold level of serum LH seemed to be necessary for ovulation, and the incidence of ovulations of six ova or more/rat increased with the increase in peak serum LH level. Preoptic-roof section, which cuts dorsal afferents to the POA, enhanced the increase in serum LH in response to POA stimulation in CLA rats, while sodium pentobarbitone anaesthesia decreased the response. In both cases, the incidence of ovulation and the number of ovulations/rat were not different from values found in POA-stimulated control CLA rats showing the same peak serum LH level. In normal cyclic rats the response of serum LH to stimulation was much greater on the morning of pro-oestrus than on that of oestrus; at prooestrus a second rise occurred between 17.00 and 19.00 h. Three days after ovariectomy the basal level of LH increased; these ovariectomized rats showed a small increase in response to a dose of 5 mC. Treatment with 20 μg oestradiol benzoate at the time of ovariectomy, however, resulted in a lowered basal LH level, but the peak response to 5 mC was almost as great as that found in similarly stimulated intact CLA rats. In intact males and in neonatally androgen-treated females the peak levels of serum LH in response to doses of 5 or 15 mC were equivalent to those in CLA females in response to doses of only 1–5 mC.

CHANGES IN PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE AFTER INJECTION OF PROGESTERONE AT VARIOUS TIMES DURING THE OVULATORY CYCLE OF THE DOMESTIC HEN (GALLUS DOMESTICUS)

1975 ◽  
Vol 67 (1) ◽  
pp. 59-70 ◽  
Author(s):  
SUSAN C. WILSON ◽  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Concentrations ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Lh Surge ◽  
Incremental Change ◽  
The Mean ◽  
Domestic Hen

SUMMARY Changes in plasma LH concentrations after i.m. injections of 0·5 mg progesterone/kg at various stages of the ovulatory cycle were measured by radioimmunoassay. Four types of response were observed. (1) When the steroid was injected between 4 h after and 12 h before an ovulation, LH levels started to rise after 15–45 min and reached peak values within 90–120 min. The mean maximal incremental change in the level of LH was 1·58 ± 0·10 (s.e.m.) ng/ml (n = 37). (2) In contrast, when progesterone was injected 12–8 h before ovulation, i.e. immediately before a spontaneous pre-ovulatory LH surge, the resulting mean maximal incremental change in LH level, 0·79 ± 0·12 ng/ml (n = 9), was significantly smaller (P < 0·001). (3) If progesterone was injected 8–4 h before ovulation, i.e. when pre-ovulatory LH levels were rising, they immediately started to rise more rapidly and reached peak values within 45 min. The maximal incremental change in the level of LH under these circumstances, 2·34 ± 0·20 ng/ml (n = 12), was significantly greater (P < 0·001 in both cases) than the changes observed in the responses 1 and 2 described above. (4) Levels of LH generally showed no incremental change in response to injections of progesterone given 4–0 h before ovulation, i.e. when pre-ovulatory LH levels were falling. It was concluded that the type of change in plasma LH levels induced by progesterone depended upon the stage of the ovulatory cycle at which the steroid was injected.

ANTIFERTILITY PROPERTIES OF BOVINE PINEAL EXTRACTS: REDUCTION OF OVULATION AND PRE-OVULATORY LUTEINIZING HORMONE IN THE RAT

1977 ◽  
Vol 85 (2) ◽  
pp. 225-234 ◽  
Author(s):  
R. J. Orts ◽  
K. M. Kocan ◽  
R. P. Johnson
Keyword(s):  
Luteinizing Hormone ◽  
Female Rats ◽  
Low Molecular Weight ◽  
Moderate Reduction ◽  
Serum Lh ◽  
Bovine Pineal Extracts ◽  
Modifying Effect ◽  
The Mean ◽  
Pineal Extracts ◽  
Lh Secretion

ABSTRACT Bovine pineal glands were extracted with acetic acid and partially purified on Sephadex G-25. Three fractions, F3, F4 and F5, were each administered to cycling female rats for 4, 2 or 1 day prior to ovulation to determine their effects on fertility, ovulation and the pro-oestrous surge of luteinizing hormone (LH). The incidence of pregnancy and the mean number of foetuses were reduced in animals after treatment with F3 or F4 but not in those treated with F5. Each of the F3 and F4 fractions significantly reduced the mean number of ova shed and the pre-ovulatory concentration of serum LH. The F5 fraction caused a moderate reduction of the pro-oestrous rise of serum LH but had no significant effect on ovulation. The data suggest that fertility in rats can be reduced by more than one substance of low molecular weight present in bovine pineal extracts through a modifying effect on LH secretion and subsequent ovulation.

Puberty, Physical Maturity, and Relative Growth of the Female Humpback Whale, Megaptera nodosa (Bonnaterre), on the Western Australian Coast

1955 ◽  
Vol 6 (3) ◽  
pp. 315 ◽  
Author(s):  
RG Chittleborough
Keyword(s):  
Body Length ◽  
Sexual Maturity ◽  
Humpback Whale ◽  
Humpback Whales ◽  
Relative Growth ◽  
Male And Female ◽  
The Mean ◽  
Sexually Mature ◽  
Western Australian

At puberty the mean body length of the female humpback whales on the Western Australian coast is 38.60 � 0.18 ft. It is demonstrated that this length gives a reliable means of calculating the proportion of sexually immature females in a series where the lengths are known. Sexual maturity (based upon the first pregnancy) may either follow immediately upon puberty or be delayed for a further year. At the approach of physical maturity (when epiphysial fusion begins) the mean body length is 45.08 � 0.29 ft. At this stage an average of 19 ovulations have occurred. On the available material, physical maturity is reached at a mean length of 44.34 � 0.72 ft, when close to 30 ovulations have occurred. Growth in body length of sexually mature females becomes very slow even before epiphysial fusion begins. The significance of the high number of ovulations before the attainment of physical maturity is discussed. The proportion of physically mature individuals amongst the females in recent catches off the Western Australian coast is extremely low (1.8 per cent. of 457 females examined). The lengths of male and female humpback whales at puberty, at the approach of physical maturity, and at physical maturity are compared.

Effect of the introduction of rams on the pulsatile release of luteinizing hormone and the onset of reproductive activity in ewe lambs

1991 ◽  
Vol 53 (2) ◽  
pp. 209-214 ◽  
Author(s):  
N. Z. N. Al-Mauly ◽  
M. J. Bryant ◽  
F. J. Cunningham
Keyword(s):  
Luteinizing Hormone ◽  
Sampling Period ◽  
Reproductive Activity ◽  
Pulse Frequency ◽  
Pulsatile Release ◽  
Ewe Lambs ◽  
The Mean ◽  
First Time ◽  
Lh Secretion

AbstractPre-pubertal ewe lambs were introduced to rams on 17 August (Tl), 12 September (T2) or 10 October (T3) or isolated from rams until 21 December (Tc) (no. = 13). Blood was taken for progesterone assay three times weekly (no. = 13) from 16 July. Blood was taken for LH assay at 15-min intervals for 8 h (no. = 8) at the time of the introduction of rams and subsequently at the time of further ram introductions. Blood was taken from Tc lambs at each ram introduction. Tl, T2 and T3 lambs ovulated for the first time 16 (s.e. 2·2) days earlier than Tc lambs but only T3 lambs ovulated after and apparently in response to the introduction of the rams. The mean baseline LH levels were higher in Tl, T2 and T3 lambs in comparison with Tc lambs at all sampling periods. The mean pulse frequency of LH secretion was significantly increased by the introduction of rams in T2 and T3 lambs in comparison with Tc lambs. The mean pulse frequency of LH secretion was greater in Tl, T2 and T3 lambs at the October sampling period in comparison to Tc lambs.

EPISODIC RELEASE OF LUTEINIZING HORMONE IN THE DOMESTIC FOWL

1975 ◽  
Vol 64 (1) ◽  
pp. 77-86 ◽  
Author(s):  
SUSAN C. WILSON ◽  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Domestic Fowl ◽  
Laying Hens ◽  
Blood Samples ◽  
Exponential Decline ◽  
The Mean ◽  
Serial Samples ◽  
Lh Secretion

SUMMARY Plasma luteinizing hormone (LH) levels were measured by radioimmunoassay in serial samples taken from intact adult cockerels, gonadectomized fowl of both sexes and laying hens. By sampling at 30 and 10 min intervals, it was shown that in cockerels LH is released episodically. Each secretory episode lasted 90–120 min and was characterized by a 100–200% rise in LH levels over a period of 10–15 min followed by a more gradual, exponential decline. Mean plasma LH levels were found to be depressed in cockerels as a result of the handling associated with taking blood samples; in cases where LH levels were most depressed, an episodic pattern of secretion could not be demonstrated. In the gonadectomized fowl, an episodic pattern of LH secretion was shown when blood samples were taken at 10 or 5 min intervals. During each secretory episode, which lasted 20–45 min, LH levels rose by 20–60%. It is suggested that the increase in mean plasma LH levels in gonadectomized fowl (30–77 ng/ml) over those in cockerels (7–16 ng/ml) is related to an increase in the frequency of the episodic release of the hormone. Episodic discharges of LH could not be demonstrated in laying hens. In these birds the mean LH levels are low (1·5–2·4 ng/ml) and consequently may be maintained by secretory episodes which are of too low an amplitude to be detectable.

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