testosterone ria ct ref ks24ct - Radim S.p.A.

RADIOIMMUNOASSAY FOR QUANTITATIVE DETERMINATION OF TESTOSTERONE IN HUMAN
SERUM
FOR IN VITRO DIAGNOSTIC USE ONLY
CLINICAL APPLICATIONS
Testosterone (M.W.: 288.4) is an androgen steroid of 19 carbon atoms. Mainly, it is synthesized in the
testes by Leydig interstitial cells, from 5-pregnenolone and progesterone, by following both Δ4 and Δ5
metabolic pathways. The Δ5 pathway seems to be predominant in the testes. A small amount is
produced by the reticular adrenal cortex, with Δ4-Androstenedione and DHEA as precursors. In the
blood it is carried by a beta-globulin. About 97-99% of circulating testosterone is bound to this carrier
protein; the remaining free fraction is considered to be biologically active. It is then excreted in the form
of glucuronides or else converted into Δ4-androstenedione which is then further metabolized, the main
catabolites being androsterone, etiocholanolone and epiandrosterone. It can also turn into
epitestosterone, an important catabolite acting on the hypothalamus as well as dihydrotestosterone
(DHT), by a 5-α-reductase. DHT is more potent than testosterone on target cells.
Testosterone determines the changes which are typical in the various pubertal stages, by stimulating the
development of the secondary sexual features (voice, height, body hair). It also acts on the penis,
scrotum, seminal vesicles and prostate. It enhances protein synthesis, makes the nitrogen, phosphorus
as well as potassium balance positive and stimulates the germinal epithelium of hair follicles. It is
involved in the differentiation of sexual behavior and regulates normal spermatogenesis. Moreover there
is a hypothalamic-pituitary negative feedback mechanism working on FSH and LH gonadotropins.
In males, testosterone levels are evaluated in cases of: hypogonadism, testicular neoplasia and
Klinefelter syndrome.
In females, testosterone levels are significant in cases of: ovarian neoplasia, hypertrichosis and Stein-
Leventhal syndrome.
PRINCIPLE OF THE ASSAY
The present method is based on a competition between labeled antigens (radioactive conjugate) and
non-labeled antigens (calibrators, samples) for binding to a number of specific sites of the antiserum
coated tubes. After the incubation, the liquid in the tubes is removed by aspiration and the radioactivity is
measured in a gamma counter.
REAGENTS PROVIDED WITH THE KIT: PREPARATION AND STABILITY
− The reagents are sufficient for 100 tubes.
− Store the kit at 2-8°C.
− The expiry date of each reagent is shown on the vial label.
CT Coated Tubes: 100 tubes (4x25) coated with rabbit polyclonal anti-Testosterone antibody. Unused
tubes should be stored at 2-8°C in the appropriate bag and accurately sealed.
CAL Calibrators: 6 vials of Testosterone in serum matrix: 1 vial of Zero Calibrator (2 mL) and 5 vials
(1.5 mL) at the following concentrations: 0.25, 0.5, 1.5, 6.0 and 15.0 ng/mL. Ready for use. Conversion:
1 ng/mL = 3.467 nmol/L. Preservative: NaN3 (< 0.1%).
NOTE: refer to the C.Q. sheet, for exact concentrations.
CONJ I 125 Radioactive Conjugate: 1 vial (50 mL) of 125 I-Testosterone in phosphate and protein buffer.
Radioactivity contents: 77.7 KBq. Ready for use and red colored. Preservative: NaN3 (< 0.1%).
CTR Control Serum: 1 vial of Testosterone in animal serum. Preservative: Thimerosal (< 0.05%).
Lyophilized. Reconstitute with 2 mL of distilled H2O. After reconstitution, store at 2-8°C for 2 weeks; for
longer periods freeze at -20°C.
NOTE: refer to the C.Q. sheet, for exact concentrations.
MATERIAL REQUIRED BUT NOT SUPPLIED
− Plastic test tubes (12 x 75 mm).
− Test tube racks.
− Adjustable, automatic micropipettes with disposable tips.
KS24CT TESTOSTERONE RIA CT
M104 - Rev.10 – 09/2007 - Pag. 8/32