The freezing and in vitro culturing of testicular biopsy tissue is a very reliable approach for the management of testicular biopsy specimens from azoospermic patients, and offers the possibility of several treatments of IVF/ICSI from a single sample.

The theca cells (TC) first become identifiable in preantral follicles after the granulosa cells (GC) begin to divide. It remains unknown when the TC first respond to LH and acquire the capacity to produce androgens. The signal initiating TC differentiation is also unknown since pre-theca cells do not contain LH receptors. Since the first wave of follicle development in the rat occurs postnatally, we correlated the function of dispersed ovarian cells from 4-, 5-, 6-, 7-, and 10-day-old rats with the morphological differentiation of TC. The largest follicles in ovaries from 4-day-old rats were primary follicles without associated TC. These cells were unable to produce cAMP or steroids in vitro in response to hCG. At 5 days, the first theca were associated with follicles containing 2-3 layers of GC. These cells were responsive to hCG, producing cAMP, progesterone, androstenedione, and androsterone. Responses to hCG increased progressively through 10 days of age. Cholesterol side-chain cleavage (P450scc), 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), and 17 alpha-hydroxylase/C17-20 lyase (P450(17 alpha)) enzymes were localized exclusively to the theca interna. Messenger RNAs for LH receptor, P450scc, 3 beta-HSD, and P450(17 alpha) were expressed prior to the time the TC become responsive to LH or morphologically differentiated. To determine the source of the signal regulating TC differentiation, dispersed cells from 4-day-old rat ovaries that were unresponsive to LH were treated with preantral follicle-conditioned medium containing thecal differentiating factor (TDF) activity. The TDF activity stimulated androgen production and expression of LH receptor, P450scc, 3 beta-HSD, and P450(17 alpha) mRNAs. These data demonstrate that a paracrine signal from the preantral follicle can initiate TC differentiation prior to expression of LH receptors. TC become responsive to LH and capable of producing androgens coincident with morphological differentiation.

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Cycles characterized by very high endogenous E2 levels resulted in significantly more oocytes per retrieval (21.4 +/- 1.7 versus 8.4 +/- 0.6; P < 0.0001), fewer postmature oocytes (1.6% +/- 1.0% versus 14% +/- 5.0%; P < 0.03), and a decreased fertilization rate (63% +/- 4.0% versus 73% +/- 3.0%; P < 0.04) compared to control cycles. There were no differences in the overall mean morphologic grade or cleavage rates between groups. However, high E2 cycles were associated with a significantly increased implantation rate (14% +/- 4.0% versus 8.0% +/- 4.0%; P < 0.01) and pregnancy rate per embryo transfer (62% +/- 16% versus 36% +/- 16%; P < 0.01) compared to controls. The incidence of spontaneous abortion did not differ between groups. CONCLUSIONS; Extremely high endogenous E2 levels do not appear to adversely affect implantation or overall cycle pregnancy rates in IVF-ET cycles. However, impaired fertilization rates in such cycles support a potential adverse effect on oocyte quality.

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