scholarly journals Lipid Content of Sheep Ovarian Follicles in Culture

1978 ◽  
Vol 31 (6) ◽  
pp. 621
Author(s):  
RP Hamilton ◽  
RF Seamark

A detailed examination was made of the lipid content of sheep ovarian follicles maintained in organ culture, and of the effect on this of human chorionic gonadotrophin.

1978 ◽  
Vol 89 (1) ◽  
pp. 166-172 ◽  
Author(s):  
T. J. Weiss ◽  
D. T. Armstrong ◽  
J. E. A. McIntosh ◽  
R. F. Seamark

ABSTRACT Theca and granulosa tissues isolated from sheep ovarian follicles of different sizes were incubated in the presence of human chorionic gonadotrophin (HCG; 5 IU/ml) or follicle stimulating hormone (FSH; 5 μg NIH-FSH-S11/ml) for 40 min. Changes in the total amounts of cyclic 3′,5′-adenosine monophosphate (cAMP) were used as an index of the responsiveness of these preparations to the hormones. Thecal tissue of both large (4–6 mm in diameter) and small (1–3 mm) follicles responded similarly to gonadotrophins. Granulosa cells from small follicles failed to respond to stimulation by HCG. FSH, however, consistently increased cAMP production in comparison with controls or cells treated with HCG. Granulosa cells of large follicles responded to both HCG and FSH.


1975 ◽  
Vol 65 (1) ◽  
pp. 19-25 ◽  
Author(s):  
P. NEAL ◽  
T. G. BAKER ◽  
K. P. McNATTY ◽  
R. J. SCARAMUZZI

SUMMARY The response of mouse ovaries maintained in organ culture to prostaglandin E2 (PGE2) and prostaglandin F2α (F2α) was assessed using quantitative histological and radioimmunoassay procedures. Prostaglandin E2 induced histological changes in the cultured follicles comparable to those induced by human chorionic gonadotrophin (HCG) and the increase in the number of oocytes undergoing preovulatory maturation over the control value was the same irrespective of the treatment (PGE2 alone, HCG alone, or PGE2 + HCG). The amount of progesterone/ ml of culture medium was also significantly higher with these preparations than in control cultures (about 125 ng/ml compared with 57 ng/ml). By contrast, 5 μg PGF2α/ml medium increased neither the number of oocytes undergoing maturation nor the concentration of progesterone in the culture medium. The latter increased when the dose of PGF2α was increased to 30 μg/ml, although the proportion of oocytes beyond the dictyate stage remained at the control level. There was no augmentation in the response (above the level for HCG alone) when HCG and PGF2α were added to the explant medium simultaneously. These results are discussed in terms of the possible mechanism of action of the various preparations.


1978 ◽  
Vol 31 (4) ◽  
pp. 405 ◽  
Author(s):  
TJ Douglas ◽  
RP Hamilton ◽  
RF Seamark

Cholesterol biosynthesis from DL-[2-14C]mevalonic acid ([l4C]MVA) was demonstrated in ovine ovarian foIlicles and isolated thecal tissues and granulosaI ceIls incubated in vitro. Thecal tissues more readily synthesized cholesterol than did granulosal ceIls when incubated separately, but in the intact follicle the newly synthesized cholesterol distributed evenly between the two tissue layers, indicating that the theca could act as a supplementary source of cholesterol for the granulosal ceIls.


1976 ◽  
Vol 29 (6) ◽  
pp. 557 ◽  
Author(s):  
RF Seamark ◽  
F Amato ◽  
Susan Hendrickson ◽  
RM Moor

A study has been made of the oxygen uptake, glucose utilization, lactate release and cellular content of adenine nucleotides of isolated sheep ovarian follicles (4-6 mm in diameter) maintained in organ culture, and of the effects on these parameters of the addition of human chorionic gonadotrophin (hCG). The mean oxygen consumption of the entire follicles when freshly isolated and of the theca and membrana components was 0�56, 1�08 and 0�05 .umol per milligram wet weight of tissue per hour respectively. About 8.umol of glucose was taken up and 16 .umol of lactate released per milligram wet weight of follicular tissue per hour during the first 24-h period of culture. This rate reduced by about 30 % for each subsequent day of culture, but was significantly increased by the addition of hCG. The mean ATP content of theca and granulosa tissues was 4�6 and 2�8 nmol/mg wet weight of tissue respectively. There was no discernable change in tissue adenine nucleotide content or energy charge ratio during the 3-day culture period, and prolonged exposure to hCG was without effect. Untreated follicles produced both oestrogen and androgens throughout the culture period. The addition of hCG resulted in a transitory stimulation in oestrogen secretion, inhibition of androgen secretion, and a marked and sustained rise in progestin secretion.


1983 ◽  
Vol 97 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Osamu Mizuno ◽  
Tsuyoshi Otani ◽  
Mariko Shirota ◽  
Shuji Sasamoto

The present investigation was performed to elucidate the mechanism of the initiation of follicular maturation after inhibition of ovulation in rats treated with pentobarbitone sodium at 13.30 h and progesterone at 14.00 h on the day of pro-oestrus (day 0 denotes the day of these treatments). Ovulation was completely inhibited and the next spontaneous ovulation occurred on day 5, the expected day of the next oestrus. Follicular responsiveness to injection of human chorionic gonadotrophin (hCG) indicated that preovulatory follicles at the time of treatment with pentobarbitone and progesterone regressed by 05.00 h on day 2. Maturation of a new set of follicles began from 17.00 h on day 2 and all rats were induced to ovulate by hCG injection by 17.00 h on day 3, the number of oocytes ovulated being comparable to normal ovulation. In the animals receiving pentobarbitone sodium and progesterone treatment, two selective rises in plasma FSH, which had peak levels at 05.00 h on day 1 and 11.00 h on day 2, were observed without a rise in LH. Preovulatory surges of FSH and LH occurred on the afternoon of day 4. These results suggest that the second rise in FSH was induced by regression of Graafian follicles present at the time of treatment with pentobarbitone sodium and progesterone and that this surge of FSH was responsible for initiation of maturation of a new set of follicles destined to ovulate in the subsequent cycle. The mechanism of induction and the role of the first rise of FSH from the night of day 0 to the morning of day 1 cannot be explained at present.


1975 ◽  
Vol 65 (1) ◽  
pp. 27-32 ◽  
Author(s):  
P. NEAL ◽  
T. G. BAKER

SUMMARY The response of mouse ovaries maintained in organ culture to follicle-stimulating hormone (FSH), luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) was assessed using quantitative histological and radioimmunoassay techniques. In terms of the induction of preovulatory maturation in follicular oocytes, 1 μg FSH/ml medium was as effective as 10 μg LH/ml. The lowest doses of HCG and LH used (0·2 i.u./ml and 1 μg/ml respectively) had no effect on oocyte maturation, whereas the response to FSH was virtually unchanged irrespective of dose (1–10 μg/ml). When the level of progesterone in the medium at the end of organ culture was used as an index of ovarian response, LH was more effective than FSH and HCG, although all the hormones induced a significant increase, irrespective of dose. These results are discussed in terms of the mode of action of gonadotrophins in the processes culminating in ovulation.


1974 ◽  
Vol 60 (1) ◽  
pp. 179-185 ◽  
Author(s):  
D. R. ABRAMOVICH ◽  
T. G. BAKER ◽  
P. NEAL

SUMMARY Foetal human testes (12–22 weeks gestation), maintained in organ culture, were treated with human chorionic gonadotrophin (HCG) and the amount of testosterone produced compared with control cultures. In all cases the testes produced testosterone, but from the 13th to 18th week of gestation significantly more testosterone was produced by, and the Leydig cell hyperplasia was maintained in, the HCG stimulated organ cultures. It is suggested that HCG is ultimately responsible for differentiation of the human male external genitalia.


Sign in / Sign up

Export Citation Format

Share Document