EFFECTS OF MATING AND INJECTION OF LUTEINIZING HORMONE RELEASING HORMONE ON SERUM LUTEINIZING HORMONE AND TESTOSTERONE CONCENTRATIONS IN RABBITS

1978 ◽  
Vol 76 (3) ◽  
pp. 417-425 ◽  
Author(s):  
C. A. BLAKE ◽  
PATRICIA K. BLAKE ◽  
NANCY K. THORNEYCROFT ◽  
I. H. THORNEYCROFT
Keyword(s):  
Luteinizing Hormone ◽  
Serum Testosterone ◽  
Serum Levels ◽  
Transient Increase ◽  
Marked Rise ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Serum Lh ◽  
Before And After ◽  
Lh Rh

The effects of coitus and injection of luteinizing hormone releasing hormone (LH-RH) on serum concentrations of LH, testosterone and dihydrotestosterone (17β-hydroxy-5α-androstan-3-one; DHT) were tested in male rabbits. Before experimentation, male and female rabbits were housed in individual cages in the same room. Male rabbits were then bled by cardiac puncture before and after placement with female rabbits or intravenous injection of LH-RH. Serum LH, testosterone and DHT were measured by radioimmunoassay. Sexual excitement (sniffing, chasing and mounting), with or without intromission, caused a marked rise in serum testosterone and DHT concentrations in only some of the bucks. These increases were accompanied or preceded by a small, transient increase in serum LH. In the rest of the bucks, sexual excitement with or without intromission had either no effect on serum levels of all three hormones, or only serum testosterone and DHT decreased during the collection period. Similar responses were measured in bucks which were housed in a room without does for 2–4 weeks before experimentation. Injection of 10, 30 or 100 ng or 50 μg LH-RH caused serum LH, testosterone and DHT to rise in all bucks tested, but the magnitude of the rises in serum testosterone and DHT were not related to the magnitude of the LH rise. In both mated and LH-RH-injected bucks, the rises in serum testosterone and DHT were greatest in animals with low initial testosterone and DHT values. Under the conditions of this study, the data suggest that: (1) serum testosterone and DHT rise in only some male rabbits after sexual excitement (with or without intromission), (2) the rises in serum testosterone and DHT are dependent on a small transient increase in serum LH and (3) sexual excitement is less likely to cause release of LH-RH in bucks with raised serum testosterone and DHT concentrations.

RESPONSE OF THE PITUITARY-TESTICULAR AXIS TO LUTEINIZING HORMONE-RELEASING HORMONE IN THE IMMATURE MALE RAT

1977 ◽  
Vol 84 (2) ◽  
pp. 254-267 ◽  
Author(s):  
H. Edward Grotjan ◽  
Donald C. Johnson
Keyword(s):  
Luteinizing Hormone ◽  
Control Level ◽  
Serum Testosterone ◽  
Male Rats ◽  
Male Rat ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Immature Male ◽  
Serum Lh ◽  
Lh Rh

ABSTRACT Follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone and androstenedione were measured by radioimmunoassays in the sera of immature male rats treated with luteinizing hormone-releasing hormone (LH-RH). A single dose of 10, 20, 40 or 80 ng of LH-RH produced a prompt increase in serum LH: significant changes in FSH were found only with the two larger doses. Serum testosterone increased to peak levels in 20 to 40 min and returned to control level by 120 min. Changes in androstenedione were temporally similar but smaller in magnitude. Four doses of 20 or 40 ng LH-RH given at 20 min intervals did not increase serum LH or testosterone concentrations above those found with a single injection; FSH was slightly higher after the fourth dose. However, 40 ng LH-RH given every 20 min for 2 h produced a dramatic increase in serum LH and FSH: serum and testicular androgens were also much higher during the second hour. A 2 h stimulation with 80 ng LH-RH given ip at 30 min intervals did not alter the response to the same treatment given 24 h later; i. e., neither the pituitary nor the gonad was primed by previous exposure to increased levels of LH-RH or gonadotrophins. These results suggest that a single pulse of LH-RH produces a predictable response in the animal, but multiple episodic stimuli produce variable responses: testes, on the other hand, produce androgens as long as gonadotrophins are available.

SERUM LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE CONCENTRATIONS IN IMMATURE FEMALE RATS TREATED WITH MULTIPLE INJECTIONS AND VARIOUS AMOUNTS OF LUTEINIZING HORMONE RELEASING HORMONE

1975 ◽  
Vol 66 (1) ◽  
pp. 13-20 ◽  
Author(s):  
D. C. JOHNSON ◽  
R. S. MALLAMPATI
Keyword(s):  
Luteinizing Hormone ◽  
Constant Stimulus ◽  
Female Rats ◽  
Intact Female ◽  
Immature Female ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Serum Luteinizing Hormone ◽  
Serum Lh ◽  
Lh Rh

SUMMARY Release of immunoreactive LH and FSH was induced in immature intact female rats by repeated injections of synthetic luteinizing hormone releasing hormone (LH-RH). Altering the dose of LH-RH (5, 10, 20, 50 ng) and the frequency of administration (every 10, 20, 30 or 60 min) over a period of 2 h produced a variety of serum LH and FSH concentrations and ratios. When the dose was a constant 20 ng but the frequency of injections was either 20 or 30 min, a steady state in serum gonadotrophin concentrations was reached within 1 h and the level remained the same during the second hour. When given every 10 min, 20 ng LH-RH produced a much higher concentration of both LH and FSH during the second hour of stimulation. Examination of the gonadotrophin levels after each injection of LH-RH showed that the pituitary response was variable in spite of a constant stimulus.

EFFECT OF SYNTHETIC LUTEINIZING HORMONE-RELEASING HORMONE (LH-RH) ON THE RELEASE OF GONADOTROPHINS IN CHILDREN AND ADOLESCENTS. VI. RELATIONS TO AGE, SEX AND PUBERTY

1974 ◽  
Vol 77 (3) ◽  
pp. 422-434 ◽  
Author(s):  
Philippe E. Gamier ◽  
Jean-Louis Chaussain ◽  
Elisabeth Binet ◽  
Ariane Schlumberger ◽  
Jean-Claude Job
Keyword(s):  
Luteinizing Hormone ◽  
Significant Variation ◽  
Blood Levels ◽  
First Year ◽  
Prepubertal Children ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Before And After ◽  
Lh Rh ◽  
First Year Of Life

ABSTRACT Plasma gonadotrophins (LH and FSH) were radio-immunoassayed before and after injection of 0.1 mg/m2 of synthetic luteinizing hormone-releasing hormone (LH-RH) in infants 1 to 12 months old, prepubertal children aged more than 12 months, and pubertal subjects of both sexes. The pubertal changes of gonadotrophins include a highly significant increase of LH pituitary mobilizable reserve in both sexes, while the FSH reserve shows a significant decrease in females and no significant variation in males. From the first year of life up to childhood, the basal blood levels of FSH and LH decrease significantly in girls but do not vary in boys, while the FSH reserve decreases significantly in girls and increases significantly in boys, the LH reserve showing a non-significant decrease in both sexes. In the first year of life, girls show a very significantly higher FSH secretion and reserve than boys, while boys have a significantly higher LH reserve than girls. After the end of the first year up to the onset of puberty, the FSH reserve remains significantly higher in girls than in boys. The interpretation of these facts is discussed.

Luteinizing hormone releasing hormone prevents testicular atrophy in golden hamsters exposed to a short photoperiod: temporal difference in effectiveness of administration of luteinizing hormone releasing hormone

1983 ◽  
Vol 96 (1) ◽  
pp. 147-154 ◽  
Author(s):  
H. J. Chen
Keyword(s):  
Luteinizing Hormone ◽  
Serum Testosterone ◽  
Testicular Atrophy ◽  
Temporal Difference ◽  
Luteinizing Hormone Releasing Hormone ◽  
Testosterone Concentration ◽  
Releasing Hormone ◽  
Golden Hamsters ◽  
Testicular Weight ◽  
Lh Rh

Exposure of male golden hamsters to short photoperiods of 6 h light: 18 h darkness led to testicular and accessory sex organ atrophy in 5 weeks. Short photoperiods also significantly depressed serum levels of LH, FSH, prolactin and testosterone in samples obtained by decapitation, but not in samples collected on the preceding day under ether anaesthesia. Injections of luteinizing hormone releasing hormone (LH-RH) at 09.00 h (lights on) or at 15.00 h (lights off) prevented testicular regression when compared with hamsters receiving injection vehicle only. However, the hamsters receiving LH-RH injections at lights on had significantly greater testicular weight and accessory sex organ (seminal vesicles and coagulating glands) weight and testosterone concentration than those receiving LH-RH at lights off. No increase in testicular weight was observed in hypophysectomized male hamsters given the same LH-RH injections and the same lighting regimen. These results indicate that LH-RH alone can prevent, at least partially, testicular and sex organ atrophy and increase serum testosterone concentration by stimulating release of LH and FSH in hamsters exposed to short photoperiods, involving temporal difference of LH-RH action. Further implications of the results are discussed.

ABNORMAL RESPONSE OF LUTEINIZING HORMONE, FOLLICLE STIMULATING HORMONE AND TESTOSTERONE TO LUTEINIZING HORMONE-RELEASING HORMONE IN CHRONIC RENAL FAILURE

1978 ◽  
Vol 87 (3) ◽  
pp. 467-475 ◽  
Author(s):  
Koichi Hasegawa ◽  
Yoshiki Matsushita ◽  
Kenzo Hirai ◽  
Seima Otomo ◽  
Teruo Okamoto ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Luteinizing Hormone ◽  
Healthy Subjects ◽  
Serum Testosterone ◽  
Serum Levels ◽  
Normal Range ◽  
Serum Lh ◽  
Lh Rh ◽  
Male Subjects

ABSTRACT Serum levels of LH, FSH, testosterone and oestradiol were measured by radioimmunoassay in 10 healthy subjects and 7 undialysed and 15 dialysed patients with chronic renal failure. The basal level of serum LH was significantly higher in patients with chronic renal failure than in healthy subjects. The basal level of serum FSH in male subjects was significantly higher in dialysed patients with chronic renal failure than in healthy subjects. Regarding testosterone secretion in male subjects and oestradiol secretion in female subjects, it was shown that the basal level of serum testosterone was significantly lower in patients with chronic renal failure than in healthy subjects, and that serum oestradiol levels were within the normal range in most of the patients with chronic renal failure. Serum levels of LH, FSH and testosterone were determined after iv injection of 100 μg of LH-RH in three groups of subjects. Responses of serum LH and FSH to LH-RH were exaggerated and prolonged in patients with chronic renal failure compared with healthy subjects. The peaks of serum LH and FSH were observed 30 min after LH-RH injection in healthy subjects while those in chronic renal failure appeared at 60 to 120 min. The levels of serum testosterone after LH-RH injection did not change within 120 min. These findings may indicate that the pituitary gonadotrophin response to LH-RH is abnormal and that the turnover of LH, FSH and LH-RH is decreased in patients with chronic renal failure.

HORMONAL EFFECTS OF TAMOXIFEN IN OLIGOSPERMIC MEN

1977 ◽  
Vol 73 (1) ◽  
pp. 171-178 ◽  
Author(s):  
K. J. WILLIS ◽  
D. R. LONDON ◽  
M. A. BEVIS ◽  
W. R. BUTT ◽  
S. S. LYNCH ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Hormonal Effects ◽  
Basal Serum ◽  
Serum Lh ◽  
Sperm Counts ◽  
Serum Androgens ◽  
Normal Men ◽  
Lh Rh

SUMMARY The hormonal effects of tamoxifen (10 mg daily for 6 months) have been studied in nine men with oligospermia. Basal concentrations of serum LH (1·7 ± 0·1 (s.e.m.) i.u./l) increased to a maximum of 4·1 ± 1·3 i.u./l (P < 0·001) after 6 months, and FSH rose from 4·9 ± 1·0 to a maximum of 7·7 ± 1·3 i.u./l after 4 months of treatment (P < 0·01). The response to luteinizing hormone releasing hormone (LH-RH) was studied at monthly intervals. Sums of increments of serum LH increased from 35 ± 4 to 92 ± 17 i.u./l at 4 months (P < 0·001) and of FSH from 14 ± 3·4 to 23 ± 3·5 i.u./l at 4 months (P < 0·01). Basal serum androgens rose from 25 ± 2·7 to 38 ± 2·4 nmol/l after 4 months of treatment (P < 0·05), and serum oestradiol-17β increased from 185 ± 25 to 631 ± 90 pmol/l by 6 months (P < 0·001). No significant changes occurred in sperm counts. Five normal men acted as controls: they were given tamoxifen for 1 week. No significant changes were observed in serum LH, FSH or release of these hormones following administration of LH-RH. Serum androgens and oestrogens however, increased significantly by day 4 of treatment (P < 0·05).

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