Improved in vitro Bioassay of Follitropin

Ritzén, Martin; Fröysa, Berit; Gustafsson, B.; Westerholm, G.; Diczfalusy, E.

doi:10.1159/000179483

Cited by 21 publications

(1 citation statement)

References 6 publications

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“…The FSH activities in the different fractions after electrophoresis were measured both by in vitro bioassay (B) and by radioimmunoassay (I) ( 12 , 13 ). The biological assay method was based upon the estimation of oestradiol produced by cultured Sertoli cells from 10-day-old rats, when incubated with graded doses of FSH in the presence of 19-hydroxyandrostenedione as a substrate ( 14 , 15 ). The relationships between the FSH in vitro B/I ratios and the FSH molecular charge were reported in 1986–1987 ( 12 , 13 ).…”

Section: Methodsmentioning

confidence: 99%

Low-glycosylated forms of both FSH and LH play major roles in the natural ovarian stimulation

Wide

Eriksson

2018

Upsala Journal of Medical Sciences

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BackgroundThe natural ovarian stimulation is mediated by four gonadotrophin glycoforms: FSHtri with three, FSHtetra with four, LHdi with two, and LHtri with three N-glycans. The aim of the study was to determine the serum concentrations of the four glycoforms and their contents of anionic monosaccharides (AMS), i.e. sialic acid (SA) and sulfonated N-acetylgalactosamine (SU) residues throughout the menstrual cycle.MethodsSerum samples were collected from 78 healthy women with regular menstrual cycles. The serum glycoform molecules were identified by their distributions at electrophoreses. Analyses were also performed after removal of terminal SA. The hormones were measured with time-resolved sandwich fluoroimmunoassays.ResultsThe concentration profiles of the four glycoforms were markedly different. FSHtri, which had a 3-fold higher biopotency than FSHtetra, had peak levels on cycle day 5 and at midcycle and nadirs on cycle days 9 and 21–23. FSHtetra had a raised level on cycle days 5–12, followed by a decrease. LHdi and LHtri had similar patterns, but the peak/nadir ratio was much more pronounced for LHdi than for LHtri, 18 versus 4. The numbers of SA residues per molecule were at a maximum around midcycle when the corresponding numbers of SU were at a minimum. The SU/SA ratio was at a minimum on cycle day 12.ConclusionThe results indicate that the LHdi and the FSHtri molecules play major roles in the natural ovarian stimulation. The SU/SA ratios per molecule favoured a prolonged circulatory half-life of all glycoforms at the midcycle phase. The observations may lead to more successful inductions of ovulation in anovulatory women.

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