Plasma proinsulin, C-peptide and sex hormone concentrations in regularly menstruating premenopausal females with ovulatory and anovulatory menstrual cycles.

AIM: Highly active females are at risk of athletic menstrual irregularities including anovulatory menstrual cycles, oligomenorrhea and even amenorrhea. On the other hand, the functional relationship between endocrine pancreas and ovaries is supported by numerous studies indicating that disturbed female sex hormone secretion coexists with insulin resistance and glucose intolerance. However, the relationship between circulating beta islet and ovarian hormones in regularly menstruating active women with ovulatory and anovulatory menstrual cycle has not been studied. METHODS: A total of 32 regularly menstruating women participated in the study. Prospective subjects monitored their BBT for 3 months before the study. The determination of plasma progesterone levels between days 5-8 and again between days 19-22 of the menstrual cycles made possible the classification of subjects as ovulating or non-ovulating. Plasma 17-beta-estradiol, testosterone, insulin, proinsulin, C-peptide and glucose concentrations were assayed on the same menstrual cycle days as progesterone. RESULTS: There were no differences in circulating insulin, C-peptide and glucose between non-ovulating and ovulating women. In contrast, in non-ovulating subjects plasma proinsulin concentrations between days 19-22 were slightly, but significantly higher than between days 5-8 of the menstrual cycle (P<0.05). Exclusively in non-ovulating women significant and positive correlation was noted between circulating proinsulin and 17-beta-estradiol in data collected from both days 5-8 and 19-22 of the menstrual cycle (P<0.008). CONCLUSIONS: Our results indicate that in the face of low circulating progesterone and subsequent anovulation circulating 17-beta-estradiol slightly, but significantly, affect either pancreatic beta-cell biosynthetic activity or proinsulin hepatic and/or renal clearance.

Influence of mitogenic activators on the structure of leukocytes.

The membrane structures of resting and activated peripheral blood mononuclear cells (leukocytes) were investigated using polarized light spectroscopy. Absorption, fluorescence and delayed luminescence spectra of leukocytes embedded in isotropic and stretched films of polyvinyl alcohol were measured. Polymer films were prepared using H2O and D2O. The perturbations of the membrane by the two mitogenic activators phytohaemagglutinin and phorbol-myristate-13-acetate were compared. Scattergrams taken using a flow cytometry method for both the resting and activated samples did not show leukocyte fragmentation or a change in the cell volume as a result of the first hour of activation. The polarized fluorescence spectra clearly showed a perturbation of the membrane structure by the activators. The absorption spectra were much less affected by activation. The delayed luminescence emission intensity of the leukocytes was low with a decay time of about 5 microseconds. The influence of phorbol-myristate-13-acetate addition on all spectral properties of the leukocytes was greater than that of phytohaemagglutinin at the same activator concentration. Polymer film deuteration influences the spectra, which shows the important role of water in maintaining the natural membrane structure. This influence is different in various regions of the emission spectrum, which shows that the various chromophores have different contacts with the environment.

Interactions between chlorophyll a and beta-carotene in nematic liquid crystals.

Fluorescence lifetime in the ps range, polarized absorption, polarized fluorescence spectra and delayed luminescence time resolved spectra were measured for chlorophyll a solutions with and without beta-carotene addition in nematic liquid crystal. Photoacoustic spectra of the same samples at various frequencies of light modulation were also taken. The frequency dependence of the photoacoustic spectra suggests that part of the excitation is converted into heat in a slow process (with a decay time of the order of ms). The lifetime results suggest that at used concentration some aggregation of the chlorophyll a occurs. The chlorophyll a molecules interact strongly with the beta-carotene forming some nonfluorescent or weakly fluorescent aggregates characterized by having various thermal deactivation yields and orientations in anisotropic matrix when compared to those of separated pigments. It seems that the aggregated forms of the chlorophylls are partially disrupted as a result of the their interaction with the beta-carotene. Singlet excitation of beta-carotene is not transferred to the fluorescent form of chlorophyll a. Delayed (in microsecond time range) luminescence of chlorophyll a is quenched by beta-carotene. This luminescence is located in the same spectral region as prompt fluorescence. Interactions between chlorophyll a and beta-carotene depend on the degree of pigment orientation and their aggregation.

Incorporation of stilbazolium merocyanines into resting and stimulated mononuclear leukocytes.

Stimulated and resting mononuclear leukocytes were incubated with a stilbazolium merocyanine dye 1-(6'-hydroxyhexyl)-4-[(4-oxocyclohexa-2,5- dienylidene)ethylidene]-1,4-dihydropyridine and immobilized in isotropic and stretched polyvinyl alcohol film. Polarized absorption, fluorescence and fluorescence excitation spectra were collected and the anisotropy of absorption and emission were calculated. Analysis of the spectra pointed to: i. the occurrence of perturbation of the membrane structure by incubation with the dye, and ii. influence of the blood serum addition, during the process of incubation with the dye, on the efficiency of incorporation of merocyanine into the cells and the degree of the dye orientation in the membrane. A small fraction of the dye molecules introduced into resting cells was found oriented to a higher degree than a large fraction incorporated into stimulated cells. The incubation time longer than 15 min caused strong changes in the membrane structure both of the resting and stimulated cells.

Incorporation of stilbazolium merocyanines into human leukocytes measured by flow cytometry.

Human peripheral blood leukocytes were incubated with thirteen various merocyanines of the stilbazolium betaine type and the fluorescence intensities of the cells were measured by flow cytometry. The fluorescence intensity of lymphocytes, monocytes and granulocytes depended on the time and temperature of incubation with the dyes. An increase in the incubation temperature enhanced the fluorescence intensity whereas washing of the cells after incubation had little influence on the observed emission. This points to incorporation of the dye molecules into the cell membrane. From the measured fluorescence intensities corrected for relative fluorescence yields, the relative efficiencies of incorporation into the cells of the various merocyanines tested were evaluated. The efficiency was dependent on the type of the cells and the lenght and side groups of the merocyanine molecules studied.