Rapid interaction between gonadotrophic hormones and the prepubertal rat ovary.

Abstract

AbstractLactic acid production by isolated ovaries from prepubertal rats was used as an experimental system to characterize the initial interaction between luteinizing hormone (LH) and human chorionic gonadotrophin (HCG) on the one hand and the ovarian tissue on the other hand. Injection of bovine LH, 30, 5 and 1 min, respectively, before extirpation of the ovaries from the rats, produced a marked increase in lactic acid production by the isolated ovaries during a following 2 hr incubation period. The effect was very pronounced already in ovaries from rats injected with LH for only 1 min before removal of the ovaries, but the effect was slightly more pronounced in the “5 rnin group”. There was, however, no significant difference between the “5 min group” and the “30 min group”. There were also persistent effects of both LH and HCG after 1–5 rnin exposure of the ovaries to the hormone in vitro followed by careful wash in hormone‐free medium. These effects did not become more pronounced when the hormone was also present during the entire 2 hr incubation period when lactic acid production was measured. The same rapid interaction between hormone and ovary was seen at both +37° C and +l ° C. Addition of an anti‐HCG serum before or together with HCG completely prevented the effect of the hormone. When the ovaries were first exposed to HCG for 1 min and then to anti‐HCG serum for 1–5 min, the anti‐serum did not abolish the hormone effect. There was no cross‐reaction between anti‐HCG serum and bovine LH. The results are discussed in relation to similar experiments with other polypeptide hormones, and in relation to various theories of the initial interaction between the hormone and the target cell.