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A. V. Nalbandov 



hens even immature follicles ovulate and all follicles appear to become 

 progressively more ovulable the longer they remain without gonadotropic 

 hormone support other than the ovulatory dose of LH. This holds true 

 only up to 12 hr after the operation, since after that time most follicles of 

 even remotely ovulable size become physically atretic and thus are incapable 

 of ovulating (Table 1). Of further interest is the fact that while most ova 



Table 2. Effect of Time on Ovulability of Follicles of Hypophysectomized Laying 

 Hens injected i.v. with 4.0 mg of LH at Time Shovvt>i 



LH preparation (Armour Lot No. R377201) contains FSH. C,, C^- 

 to hypophysectomy. Ij, Ij — ova induced by LH injection. 

 * One hen ovulated 3 follicles, one weighing 2.1 g. 



-last ova shed prior 



induced to ovulate after hypophysectomy (I^) weighed less than their normally 

 ovulated predecessors, their weights are still within the normal range. All Ig 

 ovulations, however, are very significantly below normal ovulatory size. In 

 spite of frequent and systematic attempts to induce ovulation of immature 

 follicles in intact laying hens with a gamut of doses of LH, this has never 

 been achieved in this laboratory or reported in the literature. It is interesting 

 that intact laying hens treated with progesterone will ovulate very immature 

 follicles with relative frequency. The reasons for this and the conditions 

 under which it occurs remain unknown. 



In a second experiment the question was asked whether the sensitivity of 

 follicles to LH increases with time elapsing since hypophysectomy. 

 Accordingly hens were injected with graded doses of LH at 6 or 12 hr after 

 operation. This trial showed (Table 3) that at 6 hr no ovulations were 

 induced with doses below 0.50 mg of LH, while at 12 hr 0.20 mg of LH was 

 sufficient to cause single ovulations. Furthermore, double ovulations at 12 hr 

 were produced with much lower doses of LH than the doses required to 

 cause double ovulations at 6 hr. Attention is also called to the fact that even 

 mammoth doses of LH (up to 20.0 mg) did not inhibit ovulation or reduce 

 efficiency. 



