Response of Hypophysectomized Rats to Hihly Purified Extracts of Prenant Mare Serum

Abstract

Goss and Cole 1 have shown that extracts of mare serum can be prepared testing 4000 to 7000 R.U. per mg total solids (40,000 to 70,000 R.U. per mg nitrogen). The question arises regarding the nature of the hormone present in these extracts as compared to that in untreated mare serum. Evans, et al., 2 and Hellbaum 3 have reported that more than one gonadotropic hormone is present in mare serum though these reports have not been confirmed. In the first mentioned paper the male rats showing only a Leydig tissue response were possibly sacrificed too soon to expect an effect upon the seminiferous epithelium. Further, had the time of autopsy of the females been delayed beyond 72 hours corpora lutea might have been encountered following the treatment with so-called FSH fractions. The extracts prepared by these authors were relatively crude preparations. We were interested, therefore, in determining whether or not highly purified materials would give similar evidence of fractionation of gonadotropic hormones. A fraction giving pure follicular stimulation in the female with little or no effect on the interstitial tissue of the male would give evidence of a purified follicle stimulating hormone whereas a converse relationship would indicate the presence of a luteinizing hormone.

Experimental. Two extracts were used: one, No. 15-19-2, tested 35,000 and the other, No. 17-76-4, 40,000 R.U. per mg nitrogen.∗ Four to 6 female rats, hypophysectomized on the 23rd day of age, were used at a given level for each extract. The intraperitoneal administration of a total of 30 R.U. over a 3-day period beginning on the 30th day of age produced ovaries averaging 116 mg for No. 15-19-2 and 127 mg for No. 17-76-4, on the 5th day after the initial injection.

The extracts were also tested in hypophysectomized male rats. The results on one extract, No. 15-19-2, are shown in Table I. There was a strong interstitial cell response as is indicated by the response of the accessory organs. Two rats treated similarly with No. 17-76-4 gave like results.

Thus it is seen that these extracts containing much less inert material than any previously reported for mare serum give a good follicular response in the hypophysectomized female and a strong interstitial cell response in the hypophysectomized male. In other words, in spite of the high degree of purification attained in the present extracts, no evidence was secured to support the view that mare serum contains 2 distinct hormones, one specifically affecting the interstitial tissue of the ovary and the Leydig tissue of the testis, and a second causing follicular growth in the female and germinal tissue development in the male.