Inhibition of binding of gonadal steroids to serum binding proteins by non-esterified fatty acids: the influence of chain length and degree of unsaturation

1989 ◽  
Vol 120 (2) ◽  
pp. 175-179 ◽  
Author(s):  
C. Street ◽  
R. J. S. Howell ◽  
L. Perry ◽  
S. Al-Othman ◽  
T. Chard
Keyword(s):  
Fatty Acids ◽  
Protein Binding ◽  
Unsaturated Fatty Acids ◽  
Late Pregnancy ◽  
Sex Hormone Binding Globulin ◽  
Partial Purification ◽  
Normal Female ◽  
Esterified Fatty Acids ◽  
Vitro Binding

Abstract. The effect of non-esterified fatty acids (NEFA) on the in vitro binding of testosterone, 5-alpha dihydrotestosterone and estradiol E2 to sex hormone binding globulin (SHBG) was examined using pooled normal female serum, and SHBG and albumin fractions obtained from the partial purification of late pregnancy serum. A range of saturated and unsaturated fatty acids were examined for their effect on steroid-protein binding. In normal female serum, NEFA added at physiological concentrations disrupted steroid-protein binding. The shorter chain (C8–C12) saturated acids and the poly-unsaturated acids proved to be more effective inhibitors than the longer chain saturated or mono-unsaturated acids. The greatest inhibition was obtained with E2 whereas the binding of dihydrotestosterone was least affected. With partially purified SHBG, the same concentrations of NEFA were less effective at inhibiting the binding of dihydrotestosterone and testosterone but elicited the same effect with E2. The binding of steroids to albumin appeared to be unaffected by these concentrations of NEFA.

The effect of free fatty acids on the in-vitro binding of testosterone in human plasma

1993 ◽  
Vol 136 (2) ◽  
pp. 327-330 ◽  
Author(s):  
M. J. Diver
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Pregnant Women ◽  
Human Plasma ◽  
Sex Hormone Binding Globulin ◽  
Hormone Binding ◽  
In Vitro Binding ◽  
Vitro Binding ◽  
Significant Difference

ABSTRACT The effect of supraphysiological levels of free fatty acids (FFA) on the binding of testosterone to sex-hormone binding globulin (SHBG) and on non-SHBG binding in both male plasma and plasma from pregnant women was studied. Six FFAs were added to plasma as individual acids. No alteration in testosterone binding to SHBG could be demonstrated with any of the FFAs in either male plasma or plasma from pregnant women. When the same plasma was heated to destroy SHBG binding, a highly significant (P <0·01) increase in non-SHBG binding was seen in both male plasma and plasma from pregnant women when the unsaturated FFAs oleic, linoleic and linolenic acids were added. No significant difference was demonstrated with the saturated FFAs, palmitic, stearic and arachidic acids. Journal of Endocrinology (1993) 136, 327–330

scholarly journals A kinetic rationale for functional redundancy in fatty acid biosynthesis

2020 ◽  
Vol 117 (38) ◽  
pp. 23557-23564
Author(s):  
Alex Ruppe ◽  
Kathryn Mains ◽  
Jerome M. Fox
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Average Length ◽  
Functional Redundancy ◽  
Experimental Investigations ◽  
Total Production

Cells build fatty acids with biocatalytic assembly lines in which a subset of enzymes often exhibit overlapping activities (e.g., two enzymes catalyze one or more identical reactions). Although the discrete enzymes that make up fatty acid pathways are well characterized, the importance of catalytic overlap between them is poorly understood. We developed a detailed kinetic model of the fatty acid synthase (FAS) ofEscherichia coliand paired that model with a fully reconstituted in vitro system to examine the capabilities afforded by functional redundancy in fatty acid synthesis. The model captures—and helps explain—the effects of experimental perturbations to FAS systems and provides a powerful tool for guiding experimental investigations of fatty acid assembly. Compositional analyses carried out in silico and in vitro indicate that FASs with multiple partially redundant enzymes enable tighter (i.e., more independent and/or broader range) control of distinct biochemical objectives—the total production, unsaturated fraction, and average length of fatty acids—than FASs with only a single multifunctional version of each enzyme (i.e., one enzyme with the catalytic capabilities of two partially redundant enzymes). Maximal production of unsaturated fatty acids, for example, requires a second dehydratase that is not essential for their synthesis. This work provides a kinetic, control-theoretic rationale for the inclusion of partially redundant enzymes in fatty acid pathways and supplies a valuable framework for carrying out detailed studies of FAS kinetics.

scholarly journals Characterization of the unique In Vitro effects of unsaturated fatty acids on the formation of amyloid β fibrils

PLoS ONE ◽  
2019 ◽  
Vol 14 (7) ◽  
pp. e0219465 ◽  
Author(s):  
Miki Eto ◽  
Tadafumi Hashimoto ◽  
Takao Shimizu ◽  
Takeshi Iwatsubo
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Amyloid Β ◽  
In Vitro Effects

scholarly journals The serum competitor of oestrogen–rat α1-foetoprotein interactions. Identification as a mixture of non-esterified fatty acids

1980 ◽  
Vol 187 (3) ◽  
pp. 851-856 ◽  
Author(s):  
G Vallette ◽  
C Benassayag ◽  
L Savu ◽  
J Delorme ◽  
E A Nunez ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Mass Spectrometric ◽  
The Novel ◽  
Pregnant Rat ◽  
Esterified Fatty Acids ◽  
Physiological Relevance ◽  
Lipid Moiety ◽  
Human Sera ◽  
Long Chain

The novel endogenous serum ligands of rat alpha 1-foetoprotein previously demonstrated in different mammalian sera were identified by g.l.c.–mass-spectrometric methods as a mixture of non-esterified long-chain and predominantly unsaturated fatty acids. Detailed comparative analyses of these ligands extracted from foetal- and pregnant-rat sera, rat amniotic fluid and foetal human sera are presented. We also show that an important fraction of these ligands remains associated with the rat alpha 1-foetoprotein after purification; analyses are given for the composition of this lipid moiety of the foetoprotein. The physiological relevance of these results is discussed.

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