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The endocrine environment of the human oocyte

1988; Bioscientifica; Volume: 82; Issue: 2 Linguagem: Inglês

10.1530/jrf.0.0820827

1741-7899

E. A. Lenton, H. King, Eric J. Thomas, S. K. Smith, R. I. McLachlan, Sheila MacNeil, Ian Cooke,

Sperm and Testicular Function

Follicular fluid is a unique body fluid containing a large number of biochemical components, some in extremely high concentrations, whilst in the middle of this relatively isolated biological compartment lies the arrested oocyte awaiting the signals to resume meiosis and progress towards timely ovulation. Delineation of these signals poses a challenging task. While there have been numerous reports on the concentrations of various steroids and peptides in follicular fluid after both natural and stimulated follicular growth and, similarly, the relationship between various components of oocyte maturation and the perceived signal has been studied in depth, the precise chronology of the endocrine changes relative to the sequence of oocyte maturation has not been systematically evaluated. Ideally the changing endocrine profile of the late preovulatory follicle would be best investigated by repeated frequent sampling (say every 2 h) of a single follicle. Unfortunately in the human such a longitudinal study would be difficult and so as an alternative approach we have considered the pattern of simultaneous endocrine changes in a cross-sectional group of follicles timed with respect to a common event (the start of the endogenous LH surge). The study of human follicular fluid is relatively simple because of the large volumes (2-8 ml) present in a preovulatory follicle but precise timing of the endogenous LH surge is more difficult due to the problems of frequent blood sampling. An alternative although slightly less precise method is to measure LH in frequent urine collections.